Recently, as an electronic circuit has become highly densified, there are increasing demands to make an electronic component further compact and to obtain higher performance, and along with that, for example, a multilayer ceramic capacitor has become further compact and has larger capacity, yet further improvement of the characteristics is demanded.
In response to such demands, the improvement of the characteristics is realized by controlling the boundary structure, and by placing different phases other than the main component, in the dielectric ceramic composition constituting the dielectric layer.
For example, the patent document 1 describes the dielectric ceramic comprising ABO3 as the main component, a rare earth element, M (Ni, Co, Fe, Cr, and Mn) and Si, wherein the rare earth element, M and Si are included at 70% or more of analysis points among the analysis points in the grain boundary. It also describes that this dielectric ceramic has long lifetime under high temperature high voltage load, and the small change of the capacitance over time under the DC voltage application.
However, the patent document 1 does not describe the specific content ratio of the above described elements, and the samples of the examples of the patent document 1 had a specific permittivity lower than that of the sample of the comparative example, thus there was problem that it cannot have larger capacity.
Also, the patent document 2 describes the electronic component wherein a ratio of particles with a thickness of grain boundaries of 1 nm or less is 30% or more and 95% or less.
Further, the patent document 3 describes the multilayer ceramic capacitor having a different phase including Mg—Si—O. Also, the patent document 4 describes the multilayer ceramic capacitor having the interfacial layer having an oxide of Ba—Ti—Si—Mg as the main component in between the ceramic layer and the internal electrode. Also, the patent document 5 describes the multilayer ceramic capacitor wherein Mn is segregated at the boundary between the dielectric layer and the internal electrode layer.
Also, as a different approach from the above, the patent document 6 examines to improve the specific permittivity by controlling the heat treatment condition during the firing. Specifically, during the step of firing the green multilayer body, for example the firing is carried out at 1100 to 1300° C. while suppressing the oxidation of the internal electrode layer under the reduced atmosphere having the oxygen partial pressure of 1×10−9 Pa or less. Then, reoxidation treatment of the dielectric layer is carried out by carrying out the heat treatment at 1000 to 300° C. under the oxygen partial pressure of 1×10−7 Pa or more.
However, there was a problem that the specific permittivity also declined when the dielectric layer becomes thinner, as well as the specific permittivity differed depending on the composition of the dielectric ceramic composition.
That is, according to the dielectric ceramic composition having the barium titanate as the main component in patent document 6, its specific permittivity was about 4900 at most when the thickness of the dielectric layer was 4 μm, and if the dielectric layer was made further thinner, the specific permittivity further declined.    Patent document 1: Japanese Patent Application Laid Open 2002-201065    Patent document 2: Japanese Patent Application Laid Open 2006-287045    Patent document 3: Japanese Patent Application Laid Open 2005-223313    Patent document 4: Japanese Patent Application Laid Open 2002-270458    Patent document 5: Japanese Patent Application Laid Open H11-45617    Patent document 6: Japanese Patent Application Laid Open 2001-240467